The objectives of this study are: (1) to describe the relationship among patient contributions (knowledge, perception and compliance) to their processes of care, controlling for the severity of the disease and the contributions of health care providers in a descriptive field investigation; (2) to describe the relationship between patient contributions (knowledge, perception and compliance) to their care and their health-states (clinical and psychosocial) controlling for the severity of the disease and the contributions of providers of care in a descriptive field investigation; (3) to describe the impact of systematic nursing interventions designed to improve patient contributions (knowledge, perception and compliance) to their care upon patients' outcome health states (clinical and psychosocial) controlling for severity of disease and contributions of health care providers in a controlled field experiment. The proposed research will be conducted in five distinct phases. Phase I will develop and pretest data collection instruments, establish and implement minimal standards of provider care in two study sites and select patients for the study. Phase II, a descriptive field investigation, is designed to attain objectives one and two. Phase III will analyze the data from Phase II as part of the design of the Phase IV field experiment and will include development of a nursing intervention strategy and assignment of patients to treatment groups. Phase IV, a controlled field experiment, is designed to achieve objective three. Phase V will analyze data obtained in Phase IV. All patients diagnosed as having essential hypertension and adult onset diabetes in two family health centers will be included in this study. Data on the quality of providers' contributions, the severity of patients' disease and the clinical health state of patients will be obtained from medical records. Data on knowledge, preceptions and compliance and psychosocial health states will be obtained through telephone interviews.